Trainer Philip Fenton has accepted he was in possession of banned animal remedies including steroids when his stables were searched, prosecutors have claimed.

Fenton, whose Last Instalment won the Hennessy Gold Cup at Leopardstown in February, is facing eight charges over treatments and medicines allegedly found at his yard South Lodge, Carrick-on-Suir, Co Tipperary by veterinary inspectors in January 2012.

Following lengthy and complex legal argument, lawyers for the state claimed the case against the 49-year-old is that he accepts he had the banned products.

At a late sitting of Carrick-on-Suir District Court, defence lawyers claimed the prosecution should not be brought as the regulations Fenton is alleged to have contravened date from July 2012 while the offences are alleged to have occurred in January that year.

Sean Gillane, senior counsel for the state, accused the trainer's lawyers of trying to secure immunity for him.

"In relation to this case, there is an attempt effectively to confirm immunity from prosecution on Mr Fenton in circumstances that are entirely misconceived," Gillane said.

"It appears common case that undoubtedly, if the facts are established, on January 18 2012 Mr Fenton committed acts that were contrary to the criminal law of the land, and it is the case against him that he accepts that."

No plea has been entered in the case.

Fenton's barrister Randal Hill rejected the assertion that his legal argument was designed to seek immunity from prosecution for his client.

"Nothing could be further from the truth," he said.

"That's just off the wall to say that he (Fenton) has some form of immunity from prosecution."

Judge Terence Finn will rule next Tuesday whether or not the case should proceed following objections about the offences listed on the summonses and the animal remedies regulations he is alleged to have contravened.

Defence lawyers also suggested that the judge will be asked to rule whether the District Court has the jurisdiction to hear the case in full.

They also indicated that if Judge Finn dismisses their legal argument that they will consider challenging the prosecution in the High Court in Dublin.

Fenton sat in the front row of the public gallery during the legal argument.

The prosecution is being taken by Ireland's Department of Agriculture, Food and the Marine following an inspection of Mr Fenton's yard on January 18, 2012.